Loam soil, according to the Royal Horticultural Society, is a mixture of clay, sand, silt and organic matter. This soil is loose, fertile, easily worked and drains well; it exists in two variations: clay or sandy loam.
Loam soil is suited to growing almost all plant varieties. This is possible because its three major particles, sand, silt and clay, are blended almost evenly. The sand particles hold little water but allow aeration and drainage. Clay particles retain more water, and silt combines the qualities of the sand and clay particles. Those characteristics make loam soil the most nutrient rich and fertile of soils.